Behaviour of Some Unalloyed and Alloyed Sintered Steels at Static and Dynamic Loads

2011 ◽  
Vol 672 ◽  
pp. 315-318
Author(s):  
Liviu Brânduşan
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Iron Powder ◽  
Fine Powder ◽  
Steel Powder ◽  
Sintering Process ◽  
Powder Mixtures ◽  
Sintered Steels ◽  
Static And Dynamic Loads ◽  
Sintered Materials

The behaviour of alloyed and unalloyed sintered steels in static and dynamic loading is influenced by their macro and microstructure. The characteristics of the used powder, their chemical composition, the conditions of shaping by pressing, and the parameters of the sintering process are some factors determining the structure of the steels [1, 2]. Under the same technological conditions, sintered materials were produced using iron powder of different particle size or in different powder mixtures for establishing the structure influence on some mechanical properties, The results obtained shows that the sintered materials present a higher sensitivity towards the dynamic and variable loads [2]. In the same time, it was shown that a material made from a fine powder fraction behaves, at mechanical loads, almost in the same way as an elaborated material from the same powder but with a wider particle size distribution or particles size. Using of the different powder mixtures lead to some microstructures with better mechanical properties at the intergranulars necks. Using the copper powder or the low or high alloyed iron powder in a mixture with the basic iron powder determines an improvement of the mechanical properties by changing the materials microstructure. It was found that the addition of high alloyed steel powder has the strongest effect on the fatigue resistance.

The Dimensional Change in the Sintering of a Plain Iron Powder and High-Alloyed Iron Powder Mixtures

2006 ◽  
Vol 530-531 ◽  
pp. 747-752
Author(s):  
Maurício David Martins das Neves ◽  
Nelson Karsokas Filho ◽  
Daniel Rodrigues ◽  
Lucio Salgado ◽  
Francisco Ambrozio Filho
Keyword(s):  
Iron Powder ◽  
Composite Powder ◽  
Dimensional Change ◽  
Atomic Motion ◽  
Sintering Process ◽  
Powder Mixtures ◽  
Dilatometric Analysis ◽  
Heating And Cooling ◽  
Wide Range ◽  
High Alloyed Steel

In plain iron powder or powder mixtures sintering process, it is very important to control the dimensional change. In the sintering associated events, such as lubricant removal, atomic motion and phase transformation could change dimensions over a wide range. Dilatometric analysis has shown that most contributions in the dimensional change in the sintering of iron powder mixtures were due to the combination of several effects occurring in all stages of the processing, including the heating and cooling stages. The present paper has the objective of studying the dimensional behavior and to determine the transformation temperature of a composite powder mixture of a plain iron powder with various additions of high-alloyed steel, carbon, nickel and lubricant powders, during sintering by dilatometric analysis.

scholarly journals New alloying systems for ferrous powder metallurgy precision parts

2008 ◽  
Vol 40 (1) ◽  
pp. 33-46 ◽  
Author(s):  
H. Danninger ◽  
C. Gierl
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Chemical Reactions ◽  
Sintering Process ◽  
Critical Importance ◽  
Sintered Steels ◽  
Alloy Steels ◽  
The Common

Traditionally, the common alloy elements for sintered steels have been Cu and Ni. With increasing requirements towards mechanical properties, and also as a consequence of soaring prices especially for these two metals, other alloy elements have also become more and more attractive for sintered steels, which make the steels however more tricky to process through PM. Here, the chances and risks of using in particular Cr and Mn alloy steels are discussed, considering the different alloying techniques viable in powder metallurgy, and it is shown that there are specific requirements in particular for sintering process. The critical importance of chemical reactions between the metal and the atmosphere is described, and it is shown that not only O2 and H2O but also H2 and even N2 can critically affect sintering and microstructural homogenization.

scholarly journals New alloying systems for ferrous powder metallurgy precision parts

2008 ◽  
Vol 40 (1) ◽  
pp. 33-46
Author(s):  
H. Danninger ◽  
C. Gierl
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Chemical Reactions ◽  
Sintering Process ◽  
Critical Importance ◽  
Sintered Steels ◽  
Alloy Steels ◽  
The Common

Traditionally, the common alloy elements for sintered steels have been Cu and Ni. With increasing requirements towards mechanical properties, and also as a consequence of soaring prices especially for these two metals, other alloy elements have also become more and more attractive for sintered steels, which make the steels however more tricky to process through PM. Here, the chances and risks of using in particular Cr and Mn alloy steels are discussed, considering the different alloying techniques viable in powder metallurgy, and it is shown that there are specific requirements in particular for sintering process. The critical importance of chemical reactions between the metal and the atmosphere is described, and it is shown that not only O2 and H2O but also H2 and even N2 can critically affect sintering and microstructural homogenization.

scholarly journals Processing of AISI H11 Tool Steel Powder Modified with Carbon Black Nanoparticles for the Additive Manufacturing of Forging Tools with Tailored Mechanical Properties by Means of Laser Metal Deposition (LMD)

Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 659 ◽  
Author(s):  
Oliver Hentschel ◽  
Laurids Siegel ◽  
Christian Scheitler ◽  
Florian Huber ◽  
Daniel Junker ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Carbon Black ◽  
Tool Steel ◽  
Vickers Hardness ◽  
Steel Powder ◽  
Metal Deposition ◽  
Laser Metal Deposition ◽  
Powder Mixtures ◽  
Carbon Black Nanoparticles

Within the scope of the presented work the processing of AISI H11 (1.2343 or X37CrMoV5-1) tool steel powder modified by adding carbon black nanoparticles in varying concentrations by means of Laser Metal Deposition (LMD) is extensively investigated. On the basis of single weld track experiments, multi-layered cuboid-shaped samples made out of pure AISI H11 tool steel powder as well as modified tool steel powder mixtures were manufactured by applying various process parameters. The main scientific aim of the investigations was to achieve a basic understanding of the influence of the added carbon black nanoparticles on the resulting sample properties. For that purpose, the generated specimens were first analyzed with respect to relative density, inner defects, microstructure, Vickers hardness and chemical composition. Subsequently, the mechanical properties of post-heat-treated specimens were investigated, with the focus on the yield strength (Y0.2%), by means of compression tests. We prove that by adding carbon black nanoparticles to the initial AISI H11 powder, the formation of martensitic and bainitic phases, as well as the precipitation of carbides at the grain boundaries, are enhanced. As a result, a significant increase of Vickers hardness and of the compression yield strength by up to 11% can be achieved in comparison to samples made out of the unmodified AISI H11 powder. Furthermore, it can be fundamentally demonstrated that the fabrication of parts with layer-specific variable hardness can be realized by the controlled changing of the powder mixtures used during the layer-by-layer manufacturing approach.

scholarly journals Effects of TiAl Alloy as a Binder on Cubic Boron Nitride Composites

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6335
Author(s):  
Yuxi Liu ◽  
Wei Zhang ◽  
Yingbo Peng ◽  
Guojiang Fan ◽  
Bin Liu
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Boron Nitride ◽  
Tial Alloy ◽  
Cubic Boron Nitride ◽  
Sintering Process ◽  
Good Oxidation Resistance ◽  
Tial Intermetallics ◽  
High Pressure Sintering ◽  
Sintering Method

Owing to their extreme hardness, cubic boron nitride (cBN) composites are widely used in cutting applications. The performance of cBN composites is closely related to the characteristics of the binder. Therefore, novel binders must be developed to improve the performance of cBN composites. In the present work, TiAl intermetallics were used as binders to fabricate cBN composites by employing a high-temperature and high-pressure sintering method. The phase transformation, sintering reaction mechanism, thermal stability, and mechanical properties of the resultant cBN composites were investigated. It was found that during the sintering process, Ti atoms preferentially reacted with boron nitride particles, whereas Al atoms enriched and transformed into TiAl3 phases and formed cBN/AlN, AlB2/TiN, and TiB2/TiAl3-layered structures eventually. The composites maintained good oxidation resistance at 1200 °C. A decrease in the particle size of the TiAl binder improved the uniformity of particle size distribution and increased the flexural strength of the composites.

Effect of Particle Size and Vacuum Sintering Temperature on Phase Composition and Mechanical Properties of WC-12 wt% Co Hardmetals

2012 ◽  
Vol 531-532 ◽  
pp. 3-7
Author(s):  
Shih Hsien Chang ◽  
Chung Wei Lee ◽  
Kuo Tsung Huang ◽  
Ming Wei Wu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Particle Size ◽  
Relative Density ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
Sintering Process ◽  
Vacuum Sintering ◽  
Brittle Phase ◽  
Effect Of Particle Size

The experimental results indicated that the WC-12wt% Co specimens showed excellent mechanical properties and microstructure by the optimal sintering process. The G5 specimen sintered at 1400°C/1 h achieved a relative density of 98% and a hardness of HRA 88.5. Meanwhile, the TRS increased to 2400 MPa. F12 specimens that sintered at 1350°C/1 h achieved a relative density of 99% and a hardness of HRA 92.5. The TRS was also enhanced to 2170 MPa. In this study, the η phase (Co3W3C) precipitated at a high sintering temperature. The precipitations generated by liquid phase sintering gathered in some specific regions of the specimens and reacted with the WC particles. In addition, Co3W3C was a hard and brittle phase that resulted in a low TRS for the specimens; and a large amount of η phases were detrimental to the fracture toughness of the specimens.

scholarly journals Improving the Dimensional Stability and Mechanical Properties of AISI 316L + B Sinters by Si3N4 Addition

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1798 ◽  
Author(s):  
Mateusz Skałoń ◽  
Ricardo Buzolin ◽  
Jan Kazior ◽  
Christof Sommitsch ◽  
Marek Hebda
Keyword(s):  
Mechanical Properties ◽  
Silicon Nitride ◽  
316L Stainless Steel ◽  
Steel Powder ◽  
Aisi 316L ◽  
Sintering Process ◽  
Phase Volume ◽  
Eutectic Liquid ◽  
Aisi 316L Stainless Steel ◽  
Elemental Boron

The following paper describes a new and effective method to obtain high-density sinters with simultaneously decreased distortions, produced by one press and sinter operation. This effect was achieved through the induced disappearance of the eutectic liquid phase. The study was carried out on AISI 316L stainless steel powder that was mixed with elemental boron and silicon nitride. Boron was used as a sintering process activator. The scientific novelty of this publication consists of the use of a silicon nitride as a solid-state nitrogen carrier that was intended to change the borides’ morphology by binding boron. Based on the thermodynamic calculations, 20 blends of various compositions were tested for physical properties, porosity, microstructure, and mechanical properties. Moreover, phase compositions for selected samples were analyzed. It was shown that the addition of silicon nitride as a nitrogen carrier decreases the boron-based eutectic phase volume and both increases the mechanical properties and decreases after-sintering distortions. An explanation of the observed phenomena was also proposed.

Fabrication and Mechanical Properties of ultra fine WC-6wt.%Co by Spark Plasma Sintering Process

2011 ◽  
Vol 49 (01) ◽  
pp. 40-45 ◽  
Author(s):  
Hyun-Kuk Park ◽  
Seung-Min Lee ◽  
Hee-Jun Youn ◽  
Ki-Sang Bang ◽  
Ik-Hyun Oh
Keyword(s):  
Mechanical Properties ◽  
Spark Plasma Sintering ◽  
Sintering Process ◽  
Plasma Sintering ◽  
Spark Plasma
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